Using System.Threading

I want to be able to start threads arbitrarily by my application. When I do, how can I tell how many threads are running?

Also, how can I kill a thread?

Finally, how does a thread kill itself?

VB Code:
  1. Imports System.Threading

  2.  
  3. Public Class Form1

  4.     Inherits System.Windows.Forms.Form

  5.     Dim LFile As String

  6.     Dim LFileSize As Int32 = 32767

  7.     Dim LineArray() As String

  8.     Dim NameArray() As String

  9.  
  10.     Public nThreads As Int16 = 0

  11.  
  12. #Region " Windows Form Designer generated code "

  13.  
  14.     Public Sub New()

  15.         MyBase.New()

  16.  
  17.         'This call is required by the Windows Form Designer.

  18.         InitializeComponent()

  19.  
  20.         'Add any initialization after the InitializeComponent() call

  21.  
  22.     End Sub

  23.  
  24.     'Form overrides dispose to clean up the component list.

  25.     Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)

  26.         If disposing Then

  27.             If Not (components Is Nothing) Then

  28.                 components.Dispose()

  29.             End If

  30.         End If

  31.         MyBase.Dispose(disposing)

  32.     End Sub

  33.  
  34.     'Required by the Windows Form Designer

  35.     Private components As System.ComponentModel.IContainer

  36.  
  37.     'NOTE: The following procedure is required by the Windows Form Designer

  38.     'It can be modified using the Windows Form Designer.  

  39.     'Do not modify it using the code editor.

  40.     Friend WithEvents eLabel As System.Windows.Forms.Label

  41.     Friend WithEvents Timer1 As System.Windows.Forms.Timer

  42.     Friend WithEvents txtIP As System.Windows.Forms.TextBox

  43.     Friend WithEvents cmbLocale As System.Windows.Forms.ComboBox

  44.     Friend WithEvents Label1 As System.Windows.Forms.Label

  45.     Friend WithEvents Label2 As System.Windows.Forms.Label

  46.     Friend WithEvents Button1 As System.Windows.Forms.Button

  47.     <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

  48.         Me.components = New System.ComponentModel.Container()

  49.         Me.eLabel = New System.Windows.Forms.Label()

  50.         Me.Timer1 = New System.Windows.Forms.Timer(Me.components)

  51.         Me.txtIP = New System.Windows.Forms.TextBox()

  52.         Me.cmbLocale = New System.Windows.Forms.ComboBox()

  53.         Me.Label1 = New System.Windows.Forms.Label()

  54.         Me.Label2 = New System.Windows.Forms.Label()

  55.         Me.Button1 = New System.Windows.Forms.Button()

  56.         Me.SuspendLayout()

  57.         '

  58.         'eLabel

  59.         '

  60.         Me.eLabel.Location = New System.Drawing.Point(0, 64)

  61.         Me.eLabel.Name = "eLabel"

  62.         Me.eLabel.Size = New System.Drawing.Size(336, 168)

  63.         Me.eLabel.TabIndex = 0

  64.         '

  65.         'Timer1

  66.         '

  67.         Me.Timer1.Interval = 500

  68.         '

  69.         'txtIP

  70.         '

  71.         Me.txtIP.Location = New System.Drawing.Point(96, 8)

  72.         Me.txtIP.Name = "txtIP"

  73.         Me.txtIP.Size = New System.Drawing.Size(120, 20)

  74.         Me.txtIP.TabIndex = 1

  75.         '

  76.         'cmbLocale

  77.         '

  78.         Me.cmbLocale.Location = New System.Drawing.Point(96, 32)

  79.         Me.cmbLocale.Name = "cmbLocale"

  80.         Me.cmbLocale.Size = New System.Drawing.Size(232, 21)

  81.         Me.cmbLocale.TabIndex = 2

  82.         '

  83.         'Label1

  84.         '

  85.         Me.Label1.Location = New System.Drawing.Point(8, 8)

  86.         Me.Label1.Name = "Label1"

  87.         Me.Label1.Size = New System.Drawing.Size(80, 23)

  88.         Me.Label1.TabIndex = 3

  89.         Me.Label1.Text = "IP Address"

  90.         '

  91.         'Label2

  92.         '

  93.         Me.Label2.Location = New System.Drawing.Point(8, 32)

  94.         Me.Label2.Name = "Label2"

  95.         Me.Label2.Size = New System.Drawing.Size(80, 16)

  96.         Me.Label2.TabIndex = 4

  97.         Me.Label2.Text = "Temp Locale"

  98.         '

  99.         'Button1

  100.         '

  101.         Me.Button1.Location = New System.Drawing.Point(224, 8)

  102.         Me.Button1.Name = "Button1"

  103.         Me.Button1.Size = New System.Drawing.Size(104, 24)

  104.         Me.Button1.TabIndex = 5

  105.         Me.Button1.Text = "Start | Stop"

  106.         '

  107.         'Form1

  108.         '

  109.         Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)

  110.         Me.ClientSize = New System.Drawing.Size(336, 230)

  111.         Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Button1, Me.Label2, Me.Label1, Me.cmbLocale, Me.txtIP, Me.eLabel})

  112.         Me.Name = "Form1"

  113.         Me.Text = "Downloader"

  114.         Me.ResumeLayout(False)

  115.  
  116.     End Sub

  117.  
  118. #End Region

  119.     Public Declare Function DeleteUrlCacheEntry Lib "Wininet.dll" _

  120.        Alias "DeleteUrlCacheEntryA" _

  121.       (ByVal lpszUrlName As String) As Long

  122.  
  123.     Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

  124.         Dim theNet As New System.Net.WebClient()

  125.         Dim theDataBuffer As Byte()

  126.         Dim DLFile As String

  127.         Dim x As Int16

  128.  
  129.         For x = 0 To 25

  130.             cmbLocale.Items.Add(Chr(x + 65) & ":\")

  131.         Next

  132.         theDataBuffer = theNet.DownloadData("http://" & txtIP.Text)

  133.         DLFile = System.Text.Encoding.ASCII.GetString(theDataBuffer)

  134.         LineArray = Split(DLFile, (Chr(10)))

  135.         NameArray = Split(DLFile, (Chr(10)))

  136.         For x = 0 To UBound(LineArray)

  137.             If (Len(Mid(LineArray(x), InStrRev(LineArray(x), "<td>") + 4)) < (Len(LineArray(x)) - 5)) AndAlso (InStrRev(NameArray(x), "</a>") > 0) Then

  138.                 LineArray(x) = Mid(LineArray(x), InStrRev(LineArray(x), "<td>") + 4)

  139.                 NameArray(x) = Mid(NameArray(x), InStrRev(NameArray(x), """>") + 2)

  140.                 NameArray(x) = Mid(NameArray(x), 1, InStrRev(NameArray(x), "</a>") - 1)

  141.                 If (LFileSize > Val(LineArray(x))) AndAlso (Val(LineArray(x)) > 1000) Then

  142.                     LFileSize = LineArray(x)

  143.                     LFile = NameArray(x)

  144.                 End If

  145.             Else

  146.                 LineArray(x) = ""

  147.                 NameArray(x) = ""

  148.             End If

  149.         Next

  150.     End Sub

  151.  
  152.     Private Sub Form1_Unload(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing

  153.  
  154.     End Sub

  155.  
  156.     Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

  157.         Try

  158.             Dim dlthd As DLThread = New DLThread(eLabel, cmbLocale, NameArray, txtIP)

  159.             Dim thd As Thread = New Thread(AddressOf dlthd.DoWork)

  160.             thd.Priority = ThreadPriority.BelowNormal

  161.             thd.Start()

  162.         Catch

  163.         End Try

  164.     End Sub

  165.  
  166.     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

  167.         Timer1.Enabled = Not Timer1.Enabled

  168.     End Sub

  169. End Class

  170.  
  171. Public Class DLThread

  172.     Public Declare Function DeleteUrlCacheEntry Lib "Wininet.dll" _

  173.        Alias "DeleteUrlCacheEntryA" _

  174.       (ByVal lpszUrlName As String) As Long

  175.  
  176.     Private ginLabel As Label

  177.     Private gcmbLocale As ComboBox

  178.     Private gNameArray As System.Array

  179.     Private gtxtIP As TextBox

  180.  
  181.     Public Sub New(ByRef inLabel As Label, ByVal cmbLocale As ComboBox, ByVal NameArray As System.Array, ByVal txtIP As TextBox)

  182.         ginLabel = inLabel

  183.         gcmbLocale = cmbLocale

  184.         gNameArray = NameArray

  185.         gtxtIP = txtIP

  186.     End Sub

  187.  
  188.     Public Sub DoWork()

  189.  
  190.         Try

  191.             ginLabel.Text = ""

  192.             Randomize()

  193.             Dim theNet As New System.Net.WebClient()

  194.             Dim theFile As String = gcmbLocale.SelectedItem & "file." & Rnd() * 32767

  195.             Dim DLEntry As String = "http://" & gtxtIP.Text & "/" & gNameArray(Int(Rnd() * UBound(gNameArray)))

  196.             DeleteUrlCacheEntry(DLEntry)

  197.  
  198.                         theNet.DownloadFile(DLEntry, theFile)

  199.             Kill(theFile)

  200.         Catch ee As System.Net.WebException

  201.             ginLabel.Text = ee.ToString()

  202.         End Try

  203.     End Sub

  204. End Class